Fluid rotor construction



June.2, 1959 E. A. STALKER FLUID ROTOR CONSTRUCTION Filed Jan. 3, 1955United States atene Patented June '2, 1959 FLUID ROTOR CONSTRUCTIONEdward A. Stalker, Bay City, Mich., assignor to The Stalker Corporation,a corporation of Michigan Application January 3, 1955, Serial No.479,593

9 Claims. (Cl. 230-119) This invention relates to bladed compressorrotors for exchanging energy or force with a fluid.

An object of the invention is to provide a rotor of light weight whichis economical to produce.

Other objects will appear from the specification, drawings and claims.

The above objects are accomplished by the means illustrated in theaccompanying drawings in which- Fig. 1 is an axial section through arotor according to this invention;

Fig. 2 is a front Fig. 1;

Fig. 3 is a side elevation of a blade of the rotor;

Fig. 4 is an axial view of a hub element;

Fig. 5 is a fragmentary axial section through two adjacent hub elements;

Fig. 6 is an axial View of a disk;

Fig. 7 is .an axial section of an alternate disk;

Fig. 8 is a fragmentary section on line 8-8 in Fig. 1; and

Fig. 9 is a fragmentary section on line 9-9 in Fig 1.

In a mixed flow rotor the pumped fluid is displaced outward to obtainboth radial and axial compression. To accomplish this the rotor passagesbetween blades are directly radially outward and axially rearward. Eachpassage at its inlet has a large radial depth which decreases rearward,that is downstream of the passage flow, with the radial depth at theexit substantially smaller than the depth at the inlet. Customarily theexit depth is less than half that of the inlet.

In a mixed flow compressor the inner or hub surface of each rotor flowpassage is substantially closer to the axis of rotation at the inletthan at the exit. The fluid accordingly has a substantial component ofradial flow and receives significant compression from centrifugalaction.

Rotors of the mixed flow configuration are difficult to machine if theirstructure is to be adapted to high tip speeds. Two types of constructionhave usually been employed. In one the rotor is cast of a light metalsuch as aluminum and then machined to provide smooth surfaces and toreduce the weight. In the other a forging of light metal is machined tothe desired shape.

Because of the varying contours of the passages and blades both typesare expensive. However, even more important, is the fact that lightmetals, aluminum for example, have poor fatigue properties. Since therotor and particularly the blades are subject to severe vibration whenrotated at such tip speeds as 12004400 feet per second, it is desired touse a material which has a high and definite fatigue strength. Steel(and its alloys) is such a material but its use entails machining fromforgings for the best results, and since the material is heavy so muchmore machining is involved that the cost becomes very great.

In the present invention light weight is achieved and yet the cost offabrication is lower than any of the other types heretofore used.

fragmentary view of the rotor of The blades are made of thin materialpreferably sheet metal such as a steel alloy. These are supported alongtheir length by thin disks spaced apart axially.

In order to preserve the strength of the disks against peripheral stresstherein they are preferably not slotted. It is the blades which areslotted to fit inward about the disk for forming a brazed joint.

A suitable closing means, comprising rim segments or the like, isprovided between the blades to sustain the variation in pressure of thefluid flowing in the passages between the blades.

Referring to the drawings, particularly Figs. 1 and 2, the rotor isindicated generally as 10 comprised of the blades 12 peripherally spacedabout an axis of symmetry or rotation. The blades are supported at their:root ends on a plurality of axially spaced disks comprising two enddisks 18 and 20 and intermediate disks 21-33 assembled in axially spacedrelation with radially extending spaces between each pair of disks.

As shown in Figs. 2 and 3 each blade has a series of grooves such as 36and 38 in its inner or root end. A disk fits into each groove and isfixed to the blades by fused metal between the disk and the blade at thelapping surfaces. The fused metal preferably provides fillets 39, Fig.9.

The disks are stacked axially, as shown in Fig. 1, each between two hubelements of the hub means 40. The front hub element is 42 and the rearhub element is 44. The intermediate hub elements are 50. A typical hubelement 50 is shown enlarged in Fig. 4 and in Fig. 5

A typical disk 30 is shown in Fig. 6. It should have openings 60 forventilation to facilitate soldering in a furnace employing a controlledatmosphere such as hydrogen, cracked ammonia, and the like.

The disks may also be tapered in thickness as shown by 3011 in Fig. 7.

The rotor may be mounted on a shaft 64, Fig. 1, to be rotated therewith.

As shown particularly in Figs. 2 and 8 the blades have the rotor flowpassages 70 between them each extending from an inlet 72 at the frontdownstream to the exit 74 at the rear of the rotor.

The passages are closed at the inner or root ends of the blades adjacentthe junctions of the blades with the respective disks by the rim meanswhich as shown here comprises the rim segments 82. See Figs. 1, 2, 8 and9. Preferably the segments are bonded to the blades by solder or otherfused metal and also to the disks.

The assembly supporting the blades may be called the hub structureindicated as 86.

The blades of the rotor have a sinuous contour as seen in axial sectionand fit closely to the inside surface of the compressor case 92, Fig. 1.

The disks are restrained from vibration by damper means secured to adisk at a locality intermediate the hub elements or axis of rotation andthe rim segments or inner ends of the blades. See Figs. 1 and 6.

The damper means comprises elements spaced peripherally about the axisof rotation and carried on each disk. Preferably these elements areloosely secured to each disk to bear on it under the action ofcentrifugal force. Preferably, too, the elementsextend from disk todisk.

In Fig. 1 elements or tubes 102 are loosely carried, in disk holes 60.Such tubes are shown in Fig. 6 in cross section. Each tube issuificiently flexible that it bears radially outward against the surfaceof the hole which it occupies. The tubes are positioned axially byabutting against the disks adjacent to their ends.

To facilitate low cost fabrication, the hub structure is preferably ofsheet metal construction. The disks are preferably cut by dies fromsheet metal of the proper thickness, and the rim means is preferablyformed in dies from sheet metal. Preferably the disks have a maximumthickness less than 2.5 percent of the axial distance between the enddisks 18 and 20.

The blades may be cut from sheet metal and curved by the action of dies.For very high peripheral speeds at the blade tip, the thickness of eachblade should be decreased from the root end toward the tip..

While I have illustrated specific forms of the invention, it is to beunderstood that variations may be made therein and that I intend toclaim my invention broadly as indicated by the appended claims.

I claim:

1. In combination in a bladed rotor for exchanging energy with a fluid,a hub structure comprising a plurality of axially spaced sheet metaldisks with radially extending spaces therebetween for rotation about.the axis of symmetry thereof, hub elements positioned between said disksand bonded thereto by fused metal to space said disks apart axially, aplurality of sheet metal blades extending radially outward of andperipherally spaced about said hub structure defining flow passageshaving a large radial depth at the inlets thereof and decreasing indepth toward the exits thereof, each of said blades having axiallyspaced slots each receiving a portion of each of said disks thereinto,said blades being fixed to said disks by fused metal, and rim meansfixed in said rotor at the junctions of said blades with said disks andextending from one blade to another providing inward walls bounding saidrotor flow passages.

2. In combination in a mixed flow rotor for exchanging energy with afluid, a hub structure comprising a plurality of axially spaced sheetmetal disks with radially extending spaces therebetween for rotationabout an axis of symmetry thereof, hub elements positioned between saiddisks and bonded thereto by fused metal to space said disks apartaxially, said disks increasing in diameter rearward along said axis, aplurality of sheet metal blades extending radially outward of andperipherally spaced about said hub structure defining flow passageshaving a large radial depth at the inlets thereof and decreasing indepth toward the exits thereof, each of said blades having axiallyspaced slots each receiving a portion of each of said disks thereinto,said blades being fixed to said disks by fused metal, and rim meansfixed in said rotor adjacent the inner ends of said blades and extendingfrom one blade to another providing inward walls bounding said rotorflow passages.

3. In combination in a mixed flow rotor for exchanging energy with afluid, a hub structure comprising a plurality of axially spaced sheetmetal disks with radially extending spaces therebetween for rotationabout the axis of symmetry thereof, hub elements positioned between saiddisks and bonded thereto by fused metal to space said disks apartaxially, said disks increasing in diameter rearward along said axis, aplurality of sheet metal blades extending radially outwardly of andspaced peripherally about said structure and secured thereto, each ofsaid blades decreasing in radial length rearward with said length at therear end less than at the front end, and rim means fixed to said bladesadjacent the inner ends thereof to enclose said disks.

4. In combination in a mixed flow rotor, a sheet metal hub structurecomprising a front disk and a rear disk spaced apart axially, aplurality of axially spaced intermediate disks positioned between saidfront and rear disks and secured thereto for rotation therewith aboutthe rotor axis, each said disk having an axial thickness less than 2.5percent of said axial distance between said front and rear disks, aplurality of sheet metal blades extending radially outward of and spacedperipherally about said structure defining rotor flow passages having alarge radial depth at the inlets thereof and decreasing depths towardthe exits thereof, each of said blades being secured to each ofsaiddisks, and a plurality of rim segments secured in said rotor betweenadjacent said blades to enclose said disks and bound each rotor flowpassage at the inward side thereof between adjacent said blades, eachsaid passage having an exit and an inlet with the inward side of saidexit positioned at a substantially greater radial distance from saidaxis than the inward side of said inlet is from said axis.

5. In a mixed flow compressor adapted to operate in a case, thecombination of a sheet metal hub structure comprising a front disk and arear disk spaced apart axially, a plurality of axially spacedintermediate disks positioned between said front and rear disks andsecured thereto for rotation therewith about the rotor axis, a pluralityof sheet metal blades spaced peripherally about said structure withrotor flow passages between said blades having their exits at asubstantially greater radial distance from said axis than their inlets,each of said' blades being secured to each of said disks, each of saidblades fitting closely to said case, and a plurality of rim segi' nentseach extending between said blades adjacent the root ends thereof fromfront to rear thereof to bound said passages, each of said blades havinga greater radial depth at its leading edge than at its trailing edge,each of said passages having an axial length greater than the radialdepth thereof at the exit thereof.

6. In a mixed flow compressor adapted to operate in a case, thecombination of a sheet metal hub structure comprising a front disk and arear disk spaced apart axially, a plurality of axially spacedintermediate disks positioned between said front and rear disks andsecured thereto for rotation therewith about the rotor axis, a pluralityof sheet metal blades extending outwardly of and spaced peripherallyabout said structure with rotor flow passages between said blades, eachof. said blades being secured to each of said disks, each of said bladesfitting closely to said case, and a plurality of rim segments eachextending between said blades adjacent the root ends thereof from frontto rear thereof to bound said passages, each of said blades having agreater radial depth at its leading edge than at its trailing edge,

each of said passages having an axial length greaterthantheminimumdiameter between the inward sides of said pas-sages at theinlets thereof.

7. In combination in a compressor rotor defining an axis of rotation, aplurality of sheet metal disks spaced apart axially, a plurality ofperipherally spaced sheet metal blades with each of said blades engagingwith and being secured to the radially outer portions of a plurality ofsaid spaced disks for rotation therewith about said axis tending toinduce vibrations in said disks, and vibration damper means bearing on aplurality of said spaced disks at localities intermediate said axis andthe inner ends of said blades and extending in the general axialdirection from one disk to another.

8. In combination in a compressor rotor defining an axis of rotation, aplurality of sheet metal disks spaced apart axially, a plurality ofperipherally spaced sheet metal blades with each of said blades engagingwith and being secured to the radially outer portions of a plu-- ralityof said spaced disks for rotation therewith about said axis tending toinduce vibrations in said disks, and vibration damper means bearing onsaid disks at localities intermediate said axis and the inner ends'ofsaid blades, said vibration damper means comprising elements extendingthrough a plurality of said spaced-disks atlocali- 5 ties outward fromsaid axis and bearing outward on said disks under the action ofcentrifugal force when said rotor is rotating.

9. In combination in a light weight bladed compressor rotor, a hubstructure comprising a plurality of axially spaced disks including frontand rear disks secured together for rotation about the axis of symmetrythereof, each of said disks increasing substantially in diameterrearward relative to the preceding disk, a plurality of blades extendingradially outward of and peripherally spaced about said hub structuredefining flow passages therebetween, and rim means extendingperipherally about said axis at the roots of said blades and beingbonded thereto along substantially the entire length thereof, said rimmeans lapping said front disk axially over the peripheral edge thereofand being bonded to said edge, said rim means having a radiallyextending 6 portion at said rear disk faying the surface thereofradially therealong and being bonded thereto.

References Cited in the file of this patent UNITED STATES PATENTS906,400 De Ferranti Dec. 8, 1908 2,540,991 Pn'ce Feb. 6, 1951 2,609,141Aue Sept. 2, 1952 2,622,843 Williams Dec. 23, 1952 2,649,243 StalkerAug. 18, 1953 2,650,017 Pedersen et a1 Aug. 25, 1953 2,657,008 AtkinsonOct. 27, 1953 2,743,053 Gregory et a1. Apr, 24, 1956 FOREIGN PATENTS492,801 Great Britain Sept. 27, 1938

